Configuring calico/node

The calico/node container is primarily configured through environment variables.

Environment Variables

In addition to the above, calico/node also supports the standard Felix configuration environment variables.

Note: When Calico is configured to use the Kubernetes API as the datastore, the environments used for BGP configuration are ignored—this includes selection of the node AS number (AS) and all of the IP selection options (IP, IP6, IP_AUTODETECTION_METHOD, IP6_AUTODETECTION_METHOD).

Node name determination

The calico/node must know the name of the node on which it is running. The node name is used to retrieve the Node resource configured for this node if it exists, or to create a new node resource representing the node if it does not. It is also used to associate the node with per-node BGP configuration, felix configuration, and endpoints.

When launched, the `` container sets the node name according to the following order of precedence:

1. The value specified in the NODENAME environment variable, if set.
2. The value specified in /var/lib/calico/nodename, if it exists.
3. The value specified in the HOSTNAME environment variable, if set.
4. The hostname as returned by the operating system, converted to lowercase.

Once the node has determined its name, the value will be cached in /var/lib/calico/nodename for future use.

For example, if given the following conditions:

• NODENAME=""
• /var/lib/calico/nodename does not exist
• HOSTNAME="host-A"
• The operating system returns “host-A.internal.myorg.com” for the hostname

calico/node will use “host-a” for its name and will write the value in /var/lib/calico/nodename. If calico/node is then restarted, it will use the cached value of “host-a” read from the file on disk.

IP setting

The IP (for IPv4) and IP6 (for IPv6) environment variables are used to set, force autodetection, or disable auto detection of the address for the appropriate IP version for the node. When the environment variable is set, the address is saved in the node resource configuration for this host, overriding any previously configured value.

IP setting special case values

There are several special case values that can be set in the IP(6) environemnt variables, they are:

• Not set or empty string: Any previously set address on the node resource will be used. If no previous address is set on the node resource the two versions behave differently:
  • IP will do autodetection of the IPv4 address and set it on the node resource.
  • IP6 will not do autodetection.
• autodetect: Autodetection will always be performed for the IP address and the detected address will overwrite any value configured in the node resource.
• none: Autodetection will not be performed (this is useful to disable IPv4).

IP Autodetection methods

When Calico is used for routing, each node must be configured with an IPv4 address and/or an IPv6 address that will be used to route between nodes. To eliminate node specific IP address configuration, the calico/node container can be configured to autodetect these IP addresses. In many systems, there might be multiple physical interfaces on a host, or possibly multiple IP addresses configured on a physical interface. In these cases, there are multiple addresses to choose from and so autodetection of the correct address can be tricky.

The IP autodetection methods are provided to improve the selection of the correct address, by limiting the selection based on suitable criteria for your deployment.

The following sections describe the available IP autodetection methods.

first-found

The first-found option enumerates all interface IP addresses and returns the first valid IP address (based on IP version and type of address) on the first valid interface. Certain known “local” interfaces are omitted, such as the docker bridge. The order that both the interfaces and the IP addresses are listed is system dependent.

This is the default detection method. However, since this method only makes a very simplified guess, it is recommended to either configure the node with a specific IP address, or to use one of the other detection methods.

e.g.

IP_AUTODETECTION_METHOD=first-found
IP6_AUTODETECTION_METHOD=first-found

can-reach=DESTINATION

The can-reach method uses your local routing to determine which IP address will be used to reach the supplied destination. Both IP addresses and domain names may be used.

e.g.

# Using IP addresses
IP_AUTODETECTION_METHOD=can-reach=8.8.8.8
IP6_AUTODETECTION_METHOD=can-reach=2001:4860:4860::8888

# Using domain names
IP_AUTODETECTION_METHOD=can-reach=www.google.com
IP6_AUTODETECTION_METHOD=can-reach=www.google.com

interface=INTERFACE-REGEX

The interface method uses the supplied interface regular expression (golang syntax) to enumerate matching interfaces and to return the first IP address on the first matching interface. The order that both the interfaces and the IP addresses are listed is system dependent.

e.g.

# Valid IP address on interface eth0, eth1, eth2 etc.
IP_AUTODETECTION_METHOD=interface=eth.*
IP6_AUTODETECTION_METHOD=interface=eth.*

Node readiness

The calico/node container supports an exec readiness endpoint.

Here is the help text:

$ docker exec calico-node /bin/readiness -h
Usage of dist/readiness:
  -bird
    	Specify to enable BIRD readiness checks
  -bird6
    	Specify to enable BIRD6 readiness checks
  -felix
    	Specify to enable felix readiness checks

The BIRD readiness endpoint ensures that the BGP mesh is healthy by verifiying that all BGP peers are established and no graceful restart is in progress. If the BIRD readiness check is failing due to unreachable peers that are no longer in the cluster, see decomissioning a node.